Automated methods for the preparation of radiopharmaceuticals which comprise a positron-emitting radioisotope for positron emission tomography (PET) are well-established [D. Alexoff, in “Handbook of Radiopharmaceuticals”, M. J. Welch & C. S. Redvanly (Eds.), pages 283-305 Wiley (2003)].
WO 02/051447 describes an automated synthesizer apparatus of the preparation of radiopharmaceuticals, which incorporates a disposable module containing pre-metered amounts of chemical reagents. The device is said to be particularly useful for the short-lived positron-emitting radioisotopes 11C, 13N, 15O and 18F.
Efforts have also been made to investigate automated radiopharmaceutical dispensing (APD) [Solanki, Hosp. Pharmac., 7(4), 94-98 (2000)].
For 123I-labelled radiopharmaceuticals, the conventional approach is to carry out the radiopharmaceutical preparation steps manually. Luurtsema et al [App. Rad. Isotop., 55, 783-788 (2001)] have, however, reported on an automated radiolabelling method for 123I- and 131I-labelled α-methyl tyrosine (IMT). Luurtsema et al do not use a cassette approach, and report that the expected better standardisation did not materialise for 123I, and that the variation in the automated synthesis requires further optimisation. Such optimisation was said to be necessary for each new radiopharmaceutical.
Whilst automation is recognised as having the potential to reduce operator radiation dose, prior art automated processes have also been reported to be much slower than the manual counterpart, which makes them less attractive [Solanki, Hosp. Pharmac., 7(4), 94-98 (2000)]. There is therefore a need for an automated approach which is fast, more flexible, less subject to variability, and which can generate larger batch sizes in a more efficient manner.